1. Field of the Invention
This invention relates to a semiconductor device manufacturing method, particularly, a method of manufacturing a chip size package type semiconductor device.
2. Description of the Related Art
CSP (Chip Size Package) has received attention in recent years as a packaging technology. The CSP means a small package having almost the same outside dimensions as those of a semiconductor die packaged in it. Conventionally, BGA (ball grid array) type semiconductor devices have been known as a kind of CSP type semiconductor devices. In this BGA type semiconductor device, a plurality of ball-shaped conductive terminals is arrayed in a grid pattern on one surface of the package, being electrically connected with pad electrodes of the semiconductor die. When this BGA type semiconductor device is mounted on electronic equipment, the semiconductor die is electrically connected with an external circuit on a printed circuit board by compression bonding of the ball-shaped conductive terminals to wiring patterns on the printed circuit board.
Such a conventional BGA type semiconductor device is manufactured by a following manufacturing method, for example.
First, a semiconductor substrate sectioned by a dicing line is prepared. Electronic devices are formed on a front surface of the semiconductor substrate. Then, pad electrodes connected with the electronic devices are formed on the front surface of the semiconductor substrate. Furthermore, a support body is formed on the front surface of the semiconductor substrate. Then, openings are formed along the dicing line by selectively etching a part of the semiconductor substrate from its back surface. A wiring layer is then formed, being electrically connected with the pad electrodes exposed in the openings and extending from an inside of the openings onto the back surface of the semiconductor substrate. Furthermore, the wiring layer is selectively etched to form a predetermined wiring pattern. Then, a protection layer exposing a part of the wiring layer is formed on the back surface of the semiconductor substrate including on the wiring layer, and conductive terminals are formed on a part of the wiring layer. Finally, the semiconductor substrate is separated into a plurality of semiconductor dies by dicing along the dicing line.
The relevant technology is disclosed in the Japanese Patent Application Publication No. 2002-512436.
FIG. 14 is a cross-sectional view showing one of processes of a method of manufacturing the above described semiconductor device. As shown in FIG. 14, pad electrodes 52 are formed on a front surface of a semiconductor substrate 50 with a first insulation film 51 therebetween. Furthermore, a support body 54 is formed on the front surface of the semiconductor substrate 50 including on the pad electrodes 52 with a resin layer 53 therebetween. An opening 50w is formed along a dicing line DL.
In the opening 50w formed on a back surface of the semiconductor substrate 50, however, damages, such as cracks 60, occur to a second insulation film 56 on the back surface. These cracks 60 are caused by the stress applied to the opening 50w by the semiconductor substrate 50 that is distorted when the substrate 50 is handled.
When the damage such as the cracks 60 occurs to the second insulation film 56, a solution such as etchant used in subsequent processes infiltrates therein. This causes a problem that the pad electrodes 52 formed near the second insulation film 56 and other portions of the semiconductor substrate 50 corrode away. As a result, the reliability of the semiconductor device lowers.